The present invention relates generally to a metal shear and more specifically to an improved metal shear discharge conveyor system.
Presently available shear discharge conveying systems such as shown in U.S. Pat. No. 3,670,611 issued to David J. Jarman, include a conveyor unit for moving metal from the shear blade to a stacker. The conveyor unit includes a plurality of heavy chains with welded flights. The impact of sheared metal falling unretarded onto the flights or forces resulting from edges of metal getting under the flights causes flights to break, chain sprockets to misalign, and links to separate as pins break. Link pins also fail prematurely because of insufficient lubrication and twisted chains resulting from sideway or the jumping of a sprocket by an insufficiently tensioned chain. A twisted chain and broken pins also result from the sliding action of sheared metal against the flights, and excessive drag causes the pins to break. Repair of broken flights and pins is very expensive and time-consuming. Broken flights must be repaired or replaced with new flights and welded back onto the chain. Replacing pins requires two men since the chains weigh up to one hundred pounds each; to either install a new chain or bring the ends of the chain back together to install a pin requires substantial effort.
Another problem encountered with shear conveying systems is adequately supporting metal during the sizing operation. Previous devices include sets of arms that rock upwardly from below the level of the chain conveyor flights. The tops of the arms support rollers that rotate about a transverse axis only so that any side traversing of the metal being sheared is prevented. Since the metal cannot be moved sideways on the rollers, some sizing operations become very difficult to perform. The angled arm construction also scissors or catches the scrap pieces as the arms come down after the scrap has been sheared. Another problem with the pivoting arm arrangement is that the arms occupy a fixed position and cannot move fore-and-aft for sizing different sized of cuts of steel. In addition, if light gauge metal is being sheared, the edge of the metal will nose down between the support rollers and as a result can be improperly sized, thereby resulting in wasted time, effort and material.
Previously available shear conveying systems are typically quite heavy units which are mounted on wheels. To move the units for repair or maintenance work usually requires a forklift truck. Utilizing a forklift truck to pull the conveyor in and out often results in damage to the floor adjacent the conveyor and damage to the conveyor itself as it is lifted by the forklift.
It is therefore an object of the present invention to provide an improved discharge conveying system for a shear. It is a further object to provide such a system which is more reliable and easier to repair than at least most previous discharge systems.
It is another object of the present invention to provide a shear discharge conveying system which eliminates heavy chains and welded flights. It is a further object of the invention to provide such a system which reduces or eliminates conveyor damage as a result of sheared metal falling on the conveyor carriage, chains or belts. It is yet another object to provide such a system which prevents misalignment of the conveyor or slack in the conveyor that would otherwise cause it to break or malfunction. It is still a further object to provide such a system having substantially lower maintenance costs than previous systems.
It is a further object of the invention to provide a shear discharge conveying system which prevents sheared metal from falling directly on the conveyor carriage, chains or belts and which also prevents the metal from working its way underneath portions of the conveyor. It is a further object to provide such a system which reduces failures associated with insufficient lubrication of the conveyor and wherein the conveyor produces reduced drag on the metal to reduce drag-related conveyor failure. It is another object to provide such a system with a conveyor which will maximize the amount of grab exerted by the conveyor on the sheared material for efficient conveying of the material.
It is still another object of the invention to provide a shear discharge conveying system having an improved sizing support. It is a further object to provide such a system which eliminates scissoring or catching of scrap pieces and which prevents light gauge metal from nosing down between the gauging supports.
It is still a further object of the invention to provide an improved discharge conveying system for a shear having an improved scrap removing device. It is a further object to provide such a system which prevents scrap material from contacting or fouling the conveyor.
It is yet another object of the present invention to provide a metal shear discharge conveyor system which may be more easily moved to and from its conveying position adjacent the back of a shear. It is a further object to provide such a system which can be moved and easily repaired by one man.
In accordance with the above objects, the shear discharge conveying system of the present invention includes a belt-type conveyor system which is used in place of the chain and flight-type conveyors. Belt conveyors are provided in module form which permits easy removal from the conveyor for maintenance purposes by a single man. Each module includes a belt, two end supported crown pulleys or drums, a belt support track, a belt tensioner, two module support brackets attached by bolts to the frame and couplings for the forward crown pulley drive shaft. Heavy chains with belts and flights are thereby eliminated, and lower maintenance expenses will result since each module can be easily removed by unbolting two brackets to remove the whole module, or the belt may be replaced by disconnecting a pulley drive shaft coupler to insert a new belt over the drive pulleys. As the brackets are reconnected or the drive shaft is recoupled, there is positive alignment of the pulleys. A belt tensioner is provided to automatically take up any slack in the belt, and the use of nylon-type belts reduces drag on the metal. A hydraulic drive is utilized so that the belts can be run at variable speeds to maximize the grab exerted on cut steel.
To reduce damage to the conveyor caused by sheared material falling on the belts, impact bars are placed between the conveyor modules. The impact bars are elevated above the level of the conveying surfaces during shearing process to catch falling steel. After the steel drops to the impact bars, they are lowered so that the steel comes in contact with the top of the modules where the belts convey the sheared material away from the shear in a preselected direction. Located between the modules are vertically extendible and retractable support arms, each having a ball roller at the top portion thereof. Two rows of arms are transversely aligned and extend across the conveyor to provide support for the pre-cut steel. Two hydraulic cylinders raise the front row of supports and another two cylinders raise the rear row of supports, independently or in unison. A tie bar is used to connect all of the front supports and another tie bar is used to connect all of the rear supports. The rear row of support arms may be moved fore-and-aft to accommodate different sizes of metal. Automatically adjustable length chains intermediate the supports serve to prevent light material from nosing downward between the arms during sizing. The ball support configuration permits easy traversing of the metal, and since the supports are moved vertically, no scissoring can occur to jam the arms. The fore-and-aft movement of the rear row of supports permits the supports to be adjusted to match the cut size.
Air pads are mounted on the four corners of the conveyor frame for raising the conveyor on an air cushion. Air from a compressed air supply line is attached to the air pad supports. The supports are cup-shaped and provide a layer of air on which the conveyor can float so that one man can move it in and out from the shear to perform maintenance.
A scrap gripping mechanism is provided at the shear end of the conveyor to grip sheared metal and convey it transversely to the direction of the conveyor belts. The gripping mechanism prevents scrap material from contacting the conveyor and getting caught between sections of the conveyor.
These and other objects, features and advantages of the present invention will become apparent to those skilled in the art from the description which follows and from the drawings.